EARLY TREATMENT SYMPOSIUM

Autogenic dental transplantsWilliam Northway, DDS, MSTraverse City, Mich

Everyday, viableteeth are removedfor orthodontic

purposes, includingmany from mouths withdeficiencies in otherquadrants. Although au-togenic transplantation ofteeth is often writtenabout and practiced inEurope, it is not a com-mon part of the treatmentprotocol in North Amer-

ica. This article is intended to document and summarizethe cogent issues of transplantation and to addressissues that might have deterred nonbelievers.

Dental transplantation has been practiced for cen-turies. In 1974 and 1978, Slagsvold and Bjercke,respectively, documented a 100% success rate for 34autogenic transplantations of premolars, testifying thatthis can be a recommended treatment. In subsequentstudies, Alberg, Pogrel, and, most significantly, An-dreasen reported success rates of 88%, 72%, and 95%,respectively. These studies have defined the protocol,the specifics of the technique, and many peripheralconsiderations of autogenic dental transplants. Indeed,the many works of Jens Andreasen, culminating in thetext, Atlas of Replantation and Transplantation ofTeeth, have established a standard for the managementof autogenic transplantations and avulsed teeth.

The most essential aspect of transplantation is thetechnique. The donor tooth should be dissected, notextracted. The tooth should remain outside the extrac-tion site for a minimal amount of time; therefore, therecipient site might need to be prepared in advance toallow the transplant to be immediately placed into itspreferred site. Great care must be taken to avoidtouching the periodontal ligament and to includeHertwig’s epithelial root sheath at the time of trans-

plantation. This procedure should not be performed inareas of localized infection; moreover, studies indicatethat antibiotic therapy after transplantation is beneficial.

Ideally, the recipient site should be prepared so thatthere is adequate trabecular bone surrounding the trans-plant; this should be encased in cortical bone. As withan implant, there needs to be sufficient interdental boneto protect the root complexes during the procedure. Thepreferred height of the implant is a level similar to thatfrom which it was removed. If the proximity of theinferior alveolar nerve, the maxillary sinus, or otherstructures will not permit implantation to this height,the transplant might have to be placed more toward theocclusal side. In this case, it is important that the moreelevated position not result in the gingival tissue beingplaced on the root surface. Ideally, the transplant shouldbe placed deep enough so that the site can be closedover by soft tissue, with the assistance of triple-0 blacksilk sutures.

If the tooth is mature and its size necessitates amore occlusal placement, fixation should be accom-plished in the most flexible manner possible. Orthodon-tic attachments can be used to connect the transplant toadjacent teeth with resilient wires, or an apparatus canbe created that acts like a hammock and simplyprevents the tooth from escaping from the site. Rigidfixation is absolutely contraindicated; it often leads toresorption and ankylosis. However, a transplanted toothshould never be placed so superficially as to be inocclusion.

The patient’s age and the stage of development ofthe proposed transplant are also important. If the toothis transplanted with an open apex, there is a much betterchance that the pulp chamber will revascularize. Theroot will then be more likely to grow undisturbed incontour and to reach its full potential for length. Thetooth will respond normally to vitalometer readings andwill mature to be indistinguishable from an untreatedtooth. The preferred stage of root development isbetween one-third and three-fourths complete. Treatingtoo early can lead to irregular root formation and adiminished prognosis. Conversely, an excessively de-layed approach makes revascularization difficult andincreases the chance that the tooth will require calciumhydroxide treatment, followed by endodontic therapy.

Private practice, Traverse City, Mich.Presented at the International Symposium on Early Orthodontic Treatment,February 8-10, 2002; Phoenix, Ariz.Am J Orthod Dentofacial Orthop 2002;121:592-3Copyright © 2002 by the American Association of Orthodontists.0889-5406/2002/$35.00 � 0 8/1/124795doi:10.1067/mod.2002.124795

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Interestingly, as a patient ages, the opportunity foran ideal transplantation wanes, but the development ofmaximized root length will be realized. It will, how-ever, require an orthodontic procedure. Andreasen’sexcellent study of a series of autogenic dental transplantpatients followed long-term demonstrated that 14% hada total arrest of root formation, 65% had partial arrest,and 21% had no arrest (normal root formation).

When a transplant is responding favorably, a posi-tive response to pulp vitality can be detected 2 to 4months after transplantation. This is a sign of revascu-larization, which is generally followed by obliterationof the pulp canal. There is a regeneration of capillaryvessels through the apical foramen, and the pulp cham-ber develops a normal contour and radiographic appear-ance. The response can vary, of course, and partialobliteration can occur, often resulting in irregular cal-cification and the disappearance of the pulp chamber. Ineven less favorable situations, the obliteration might befollowed by an ingrowth of bone and periodontalligament. In most cases, the transplant heals in the newsite. The tooth responds to the vitalometer, but responsediminishes, especially when the canal has calcified. Inthese less favorable cases, the response is due more toelectrical stimulation at the periodontal ligament than tothe vitality of the pulp organ.

Orthodontic forces should not be applied to atransplanted tooth during the first 3 to 6 months; whenforce is initiated, the amount and duration of applica-tion should be minimized. Andreasen describes a win-dow of opportunity at 6 to 9 months after transplanta-tion, while the revascularization is being maximized.He suggests that the orthodontic forces should beremoved by 9 months, when obliteration of the pulpcanal should be conspicuous.

Premolars and third molars are by far the favoritechoices for autogenous transplantation. The root shapeand the relative dispensability of these teeth, and thelater age at which they remain viable, make themdesirable for transplantation. Transplantation should bea preferred method of replacement in many cases ofagenesis. Patients with several missing teeth are excel-lent candidates, especially if the maxillary premolarsare involved. Often the proximity of the maxillary sinusleaves these areas with a depth of alveolar bone

inadequate for placing an implant. Transplant place-ment will initiate an increase in the depth of alveolarbone; its roots will often grow up into the sinus,improving restorative opportunities in this difficultregion. Certainly, wisdom teeth should not be discardeduntil it can be ascertained that all remaining permanentteeth have erupted or will erupt normally. A trans-planted wisdom tooth can make a wonderful substitutefor an ankylosed permanent tooth. Care must be takenwhen selecting patients and surgeons.

Autotransplantation is extremely technique-sensi-tive; the prognosis is highly variable and is basedlargely on the person rendering the treatment. Moretransplants are performed in Scandinavia than in NorthAmerica, perhaps because of disparities in government-provided care and the emphasis that North Americanorthodontists place on nonextraction treatment. Never-theless, the Scandinavians have evolved a highly suc-cessful procedure.

REFERENCES

1. Slagsvold O, Bjercke B. Autotransplantation of premolars withpartly formed roots: a radiographic study of root growth. Am JOrthod 1974;66:355-66.

2. Slagsvold O, Bjercke B. Indications for autotransplantation incases of missing premolars. Am J Orthod 1978;74:241-57.

3. Ahlberg K, Bystedt H, Eliasson S, Odenrick L. Long-termevaluation of autotransplanted maxillary canines with completedroot formation. Acta Ondontol Scand 1983;41:23-31.

4. Pogrel M. Evaluation of over 400 autogenous tooth transplants. JOral Maxillofac Surg 1987;45:205-11.

5. Andreasen JO, Paulsen HU, Yu Z, Ahlquist R, Bayer T, SchwartzO. A long-term study of 370 autotransplanted premolars. Part I.Surgical procedures and standardized techniques for monitoringhealing. Eur J Orthod 1990;12:3-13.

6. Andreasen JO, Paulsen HU, Yu Z, Ahlquist R, Bayer T, SchwartzO. A long-term study of 370 autotransplanted premolars. Part II.Tooth survival and pulp healing subsequent to transplantation. EurJ Orthod 1990; 12:14-24.

7. Andreasen JO, Paulsen HU, Yu Z, Ahlquist R, Bayer T, SchwartzO. A long-term study of 370 autotransplanted premolars. Part III.Periodontal healing subsequent to transplantation. Eur J Orthod1990;12:25-37.

8. Andreasen JO, Paulsen HU, Yu Z, Ahlquist R, Bayer T, SchwartzO. A long-term study of 370 autotransplanted premolars. Part IV.Root development subsequent to transplantation. Eur J Orthod1990;12:38-50.

9. Andreason JO. Atlas of Replantation and transplantation of teeth.Friborg (Switzerland): MediGlobe SA: 1992.

American Journal of Orthodontics and Dentofacial OrthopedicsVolume 121, Number 6

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